#ifndef _SNOISE_CGINC_
#define _SNOISE_CGINC_

// -------------------------------------------------------------------
// Description : Array and textureless GLSL 2D simplex noise function.
// Author : Ian McEwan, Ashima Arts.
// Maintainer : ijm
// Lastmod : 20110822 (ijm)
// License : Copyright (C) 2011 Ashima Arts. All rights reserved.
// Distributed under the MIT License. See LICENSE file.
// https://github.com/ashima/webgl-noise
// 

float3 mod289(float3 x) 
{
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

float2 mod289(float2 x) 
{
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

float3 permute(float3 x) 
{
  return mod289(((x*34.0)+1.0)*x);
}

float snoise(float2 v)
{
  float4 C = float4(  0.211324865405187, // (3.0-sqrt(3.0))/6.0
                      0.366025403784439, // 0.5*(sqrt(3.0)-1.0)
                     -0.577350269189626, // -1.0 + 2.0 * C.x
                      0.024390243902439); // 1.0 / 41.0
// First corner
  float2 i = floor(v + dot(v, C.yy) );
  float2 x0 = v - i + dot(i, C.xx);

// Other corners
  float2 i1;
  //i1.x = step( x0.y, x0.x ); // x0.x > x0.y ? 1.0 : 0.0
  //i1.y = 1.0 - i1.x;
  i1 = (x0.x > x0.y) ? float2(1.0, 0.0) : float2(0.0, 1.0);
  // x0 = x0 - 0.0 + 0.0 * C.xx ;
  // x1 = x0 - i1 + 1.0 * C.xx ;
  // x2 = x0 - 1.0 + 2.0 * C.xx ;
  float4 x12 = x0.xyxy + C.xxzz;
  x12.xy -= i1;

// Permutations
  i = mod289(i); // Avoid truncation effects  permutation
  float3 p = permute( permute( i.y + float3(0.0, i1.y, 1.0 )) + i.x + float3(0.0, i1.x, 1.0 ));

  float3 m = max(0.5 - float3(dot(x0,x0), dot(x12.xy,x12.xy), dot(x12.zw,x12.zw)), 0.0);
  m = m*m ;
  m = m*m ;

// Gradients: 41 points uniformly over a line, mapped onto a diamond.
// The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)

  float3 x = 2.0 * frac(p * C.www) - 1.0;
  float3 h = abs(x) - 0.5;
  float3 ox = floor(x + 0.5);
  float3 a0 = x - ox;

// Normalise gradients implicitly by scaling m
// Approximation of: m *= inversesqrt( a0*a0 + h*h );
  m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h );

// Compute final noise value at P
  float3 g;
  g.x = a0.x * x0.x + h.x * x0.y;
  g.yz = a0.yz * x12.xz + h.yz * x12.yw;
  return 130.0 * dot(m, g);
}

//
// Description : Array and textureless GLSL 2D/3D/4D simplex
// noise functions.
// Author : Ian McEwan, Ashima Arts.
// Maintainer : ijm
// Lastmod : 20110822 (ijm)
// License : Copyright (C) 2011 Ashima Arts. All rights reserved.
// Distributed under the MIT License. See LICENSE file.
// https://github.com/ashima/webgl-noise
//


float4 mod289(float4 x) 
{
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

float4 permute(float4 x) 
{
     return mod289(((x*34.0)+1.0)*x);
}

float4 taylorInvSqrt(float4 r)
{
  return 1.79284291400159 - 0.85373472095314 * r;
}

float snoise(float3 v)
{
  float2 C = float2(1.0/6.0, 1.0/3.0) ;
  float4 D = float4(0.0, 0.5, 1.0, 2.0);

// First corner
  float3 i = floor(v + dot(v, C.yyy) );
  float3 x0 = v - i + dot(i, C.xxx) ;

// Other corners
  float3 g = step(x0.yzx, x0.xyz);
  float3 l = 1.0 - g;
  float3 i1 = min( g.xyz, l.zxy );
  float3 i2 = max( g.xyz, l.zxy );

  // x0 = x0 - 0.0 + 0.0 * C.xxx;
  // x1 = x0 - i1 + 1.0 * C.xxx;
  // x2 = x0 - i2 + 2.0 * C.xxx;
  // x3 = x0 - 1.0 + 3.0 * C.xxx;
  float3 x1 = x0 - i1 + C.xxx;
  float3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
  float3 x3 = x0 - D.yyy; // -1.0+3.0*C.x = -0.5 = -D.y

// Permutations
  i = mod289(i);
  float4 p = permute( permute( permute(
             i.z + float4(0.0, i1.z, i2.z, 1.0 ))
           + i.y + float4(0.0, i1.y, i2.y, 1.0 ))
           + i.x + float4(0.0, i1.x, i2.x, 1.0 ));

// Gradients: 7x7 points over a square, mapped onto an octahedron.
// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
  float n_ = 0.142857142857; // 1.0/7.0
  float3 ns = n_ * D.wyz - D.xzx;

  float4 j = p - 49.0 * floor(p * ns.z * ns.z); // mod(p,7*7)

  float4 x_ = floor(j * ns.z);
  float4 y_ = floor(j - 7.0 * x_ ); // mod(j,N)

  float4 x = x_ *ns.x + ns.yyyy;
  float4 y = y_ *ns.x + ns.yyyy;
  float4 h = 1.0 - abs(x) - abs(y);

  float4 b0 = float4( x.xy, y.xy );
  float4 b1 = float4( x.zw, y.zw );

  //float4 s0 = float4(lessThan(b0,0.0))*2.0 - 1.0;
  //float4 s1 = float4(lessThan(b1,0.0))*2.0 - 1.0;
  float4 s0 = floor(b0)*2.0 + 1.0;
  float4 s1 = floor(b1)*2.0 + 1.0;
  float4 sh = -step(h, float4(0, 0, 0, 0));

  float4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
  float4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;

  float3 p0 = float3(a0.xy,h.x);
  float3 p1 = float3(a0.zw,h.y);
  float3 p2 = float3(a1.xy,h.z);
  float3 p3 = float3(a1.zw,h.w);

//Normalise gradients
  float4 norm = taylorInvSqrt(float4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
  p0 *= norm.x;
  p1 *= norm.y;
  p2 *= norm.z;
  p3 *= norm.w;

// Mix final noise value
  float4 m = max(0.6 - float4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
  m = m * m;
  return 42.0 * dot( m*m, float4( dot(p0,x0), dot(p1,x1),
                                dot(p2,x2), dot(p3,x3) ) );
}

#endif
